The impact of gravel on crop management

Location: Western Australia (Statewide)

Project Start Date: January 2013

Project End Date: December 2013

Project Aim: The Gravel project is a one year study that will be conducted by WMG Ambassador, Bill Bowden. Gravel is a largely ignored but important component of soils, particularly in the high rainfall zone (HRZ) of Western Australia (WA).

Bill Bowden said “Gravel, as an often inert component of a soil, has a diluting effect on the amount of stored water and nutrients. At the same time, it has a concentrating effect on inputs such as herbicides fertilisers and soil ameliorants. It has implications for infiltration and runoff rates, for load bearing and compaction. It is an essential parameter for the calculation of carbon and soil fertility budgets. Soils are discriminated by farmers for management and explanation on the basis of visible surface gravel. Some classes of gravels are not necessarily inert and can absorb water and nutrients. Gravels introduce heterogeneity into soils which can have positive and negative effects on crop production”.

This project will use an understanding of the gravel content of soils to re-investigate a range of soil processes with the objective of better managing the gravel soils of WA. The results will have relevance for the wide geographic distribution of gravelly and stony soils cropped in Australia. An understanding of how the gravel content of the soil interacts with the water balance, plant nutrition and crop growth is an area worthy of study in WA, particularly as the cropping centre of gravity moves into the HRZ.